The "Proteins" Gordon Research Conference is a biannual conference with a long and distinguished history. The conference aims to bring together researchers who are actively involved in research into the biochemistry and biophysics of protein structure and function. In choosing speakers and topics, we solicited input from across the protein science community. Many suggestions are incorporated into our final program. Professor Regan was co-chair of the 2001 Proteins conference and Professor Klevit was a speaker. This conference was notable for the range and depth of discussion and, most importantly, for the active participation of a large fraction of the attendees. We aim to emulate the 2001 meeting in this regard and, in addition, to enhance participation by choosing a few speakers from the poster sessions to present their work orally. The specific areas of focus we have chosen, based upon previous conferences, input from the scientific community, recent progress and discoveries, and quality of potential speakers are: 1) Structure and function of membrane proteins 2) Proteins as therapeutics and drug targets 3) Proteins in disease 4) New structures and new methods 5) Protein-protein interactions 6) Single molecules and protein machines 7) Protein folding and stability 8) The unfolded state The research stimulated by the conference should directly benefit the progress of biomedical research across a fairly broad field. Finally, the organizers are particularly sensitive to ensuring the full representation of women and minorities in this meeting.